1) Am I right in thinking 「UNIXおよびそれと互換性」is parsed as 「UNIXおよび(、)それと互換性をもつ Linux」, meaning something like "Linux, which is compatible with and even called by the name UNIX"?

2) The うかがい is paired with その簡潔性・効率性・移植性の高さは, right?

Here's my attempted translation (not including the first sentence):

The degree of its [the C language's] conciseness, efficiency, and portability, may be understood from the fact that even now, some thirty-plus years since its conception, many other application programs, and various operating systems such as Linux (which is compatible with and even called by the name UNIX), are developed using primarily the C language.

Just one thing I'm not quite sure (because of my poor English comprehension) is "Linux, which is compatible with and even called by the name UNIX" part.

UNIXおよびそれと互換性をもつLINUXなどのOSUNIX, and some (other) OSs that are compatible with (the UNIX), such as Linux....I know my English sucks but, meaning-wise, the primary example the writer wanted to mention was UNIX, not Linux. I don't know if it's already clear in your translation, though. Just in case.

Just one thing I'm not quite sure (because of my poor English comprehension) is "Linux, which is compatible with and even called by the name UNIX" part.

UNIXおよびそれと互換性をもつLINUXなどのOSUNIX, and some (other) OSs that are compatible with (the UNIX), such as Linux....I know my English sucks but, meaning-wise, the primary example the writer wanted to mention was UNIX, not Linux. I don't know if it's already clear in your translation, though. Just in case.

Your English is quite fine, other than that "...are compatible with (the UNIX)" shouldn't have "the".

This is certainly not clear in my translation. Thank you for pointing it out.

In that case, what is the meaning of UNIXおよび? "UNIX itself"? Is it 及び or お呼び? I couldn't really understand the meaning using either, though 及び seems much more natural in context - but I went with お呼び for my "called UNIX" version. If it's 及び, is it "reaching even to UNIX", or maybe best as "including UNIX"?

Also, my translation didn't account for the など after Linux, as yours does. Thanks for the clarification!

yangmuye wrote:{{...}}(は)殆どがＣ言語を用いて開発されているAlmost all {{...}} are developed using the C(As for {...}, almost all of them are ...)

Hm, I would like to parse it like that too, but I don't think it's right: mainly because it would be wildly untrue to say that, at least for the アプリケーションプログラム part. I don't believe it's sensible to say that the vast majority of applications in the world were written in the C programming language. I'm thinking the ほとんど is there mainly because, while there are many application programs that are written entirely in C, there are no operating systems that are written entirely in C (at some point, some assembly code is inevitable). Of course, the ほとんど applies to both, and as far as I can tell grammatically, it could be read as you read it. NileCat, is there some nuance that distinguishes this sentence as clearly meaning one or the other of "Most applications/OSs are written using C" versus "Many applications/OSs are written using mostly C"? Maybe the presence of 多く in 多くのアプリケーションプログラム?

yangmuye wrote:{{...}}(は)殆どがＣ言語を用いて開発されているAlmost all {{...}} are developed using the C(As for {...}, almost all of them are ...)

Hm, I would like to parse it like that too, but I don't think it's right: mainly because it would be wildly untrue to say that, at least for the アプリケーションプログラム part. I don't believe it's sensible to say that the vast majority of applications in the world were written in the C programming language. I'm thinking the ほとんど is there mainly because, while there are many application programs that are written entirely in C, there are no operating systems that are written entirely in C (at some point, some assembly code is inevitable). Of course, the ほとんど applies to both, and as far as I can tell grammatically, it could be read as you read it. NileCat, is there some nuance that distinguishes this sentence as clearly meaning one or the other of "Most applications/OSs are written using C" versus "Many applications/OSs are written using mostly C"? Maybe the presence of 多く in 多くのアプリケーションプログラム?

I never thought about this question. Since you can't avoid writing assembly to controll the hardware, it can be regarded as a pure C programm as long as its logic is expressed in C.I just interprete the sentence as APPが多くＣ言語を用いて開発されている。そして、OSも殆どＣ言語を用いて開発されている。